The invention is related to telephony communications systems. More specifically, the invention is related to methods performed by an IP telephony system to setup and bill for telephony communications.
When a user of an IP telephony system wishes to conduct a telephony communication, the user's telephony device sends a telephony communication setup request to an element of the IP telephony system, such as a proxy server or a gateway. If the user's IP telephony device and the element of the IP telephony system communicate with one another using the Session Initiation Protocol (SIP), the telephony communication setup request is typically in the form of a SIP Invite message.
When an element of an IP telephony system such as a proxy server receives a SIP Invite message from a user's telephony device, the proxy server typically will first try to authenticate the user's telephony device as authorized to receive the requested telephony services. This usually involves messaging that passes back and forth between the proxy server and the user's telephony device. The authentication process also may involve messaging that passes between the proxy server and other elements of the IP telephony system if the proxy server must obtain information about the user's telephony device, or the user, to determine whether or not the user is authorized to receive the requested telephony services. It would be desirable to eliminate some of the messaging traffic that presently occurs during such an authentication process.
After a telephony communication that was carried via an IP telephony system has been completed, the IP telephony system gathers and records information about the telephony communication. This information is typically gathered by a call detail record (CDR) unit that generates one or more call detail records (CDRs) for the telephony communication. A billing unit of the IP telephony system uses information in the CDRs to determine if a user should be charged for the telephony communication, and if so, how much. The billing unit may obtain and utilize information about how much to charge for a communication from a rating unit.
A rating unit supplies information about how much individual users should be charged for a telephony communication. The rating unit tracks the billing or rate plans that apply to each user, and the rating unit supplies the charge information to the billing unit or the CDR unit for billing purposes. In some embodiments, the rate information is recorded into the CDR. However, in alternate embodiments, the rate information may be provided directly to a billing system that calculates charges based on information in the CDRs.
In some IP telephony systems, the CDR unit or the billing unit sends every individual CDR to the rating unit and requests charge information for the telephony communication that gave rise to the CDR. However, the CDR unit and/or the billing unit do not necessarily require such charge information for all CDRs. For example, if a CDR is for an outgoing call that originated from a user's telephony device and that was placed to a telephone number in a different country, it is necessary to charge the user for the call. On the other hand, if a CDR is for an inbound call that was completed to a user's telephony device, the user will not be charged for the incoming call.
Rather than sending all CDRs to the rating unit, it would be desirable to send to the rating unit, only those CDRs that are for telephony communications that will result in charges to the user. Operating in this fashion would eliminate unnecessary message traffic, and reduce the burden placed on the rating unit.